A drinker who frequents a bar or tavern, and who drinks alcoholic beverages to excess.

Suzanne a local bar fly, would flirt with any guy whom she thought might buy her a drink.
Fat Chris was the local Bar Fly at Copelands Bar, drinking fist fulls of Vodka and hitting on all the women.
I meet Anne at Copelands Bar, a stylish educated women whom hardly looked the bar fly type,so I asked her out on a date.